Field Setting

The project was conducted in the New Botanical Garden in Marburg on a meadow area with low visitor traffic (Fig. 5). Three flight cages were installed here, each containing an experimental setup with a camera trap, host plants, and a group of test insects (Fig. 6). The species Osmia bifornis and Vanessa cardui were selected as representative diurnal insects, and the moth species Lymatria dispar was chosen as a representative nocturnal insect, to test whether the trap is suitable for both day and night insects. Due to delivery and time issues, the species Osmia bifornis and Lymatria dispar are no longer available for analysis, as they had already reached the end of their life cycle before the construction of the flight cages was completed. Therefore, we are forced to reduce our focus solely to the species Vanessa cardui (Fig. 4).

Figure 5: Three flight cages with experimental setup. The solar panel for power supply is in the center.

The butterfly pupae were placed in the flight cages to hatch. Fresh host plants were regularly placed in a water-filled container for the adult insects. The camera trap was attached to a wooden stake, pointing towards the ground. The holder with the colored panels was mounted just above the ground, at the height of the meadow herbs (Fig. 6). The holder always contained two panels of the same color (yellow, blue, flower texture) but made of two different materials: matte rigid foam and acrylic glass. The panel sets were regularly swapped between the flight cages to compensate for potential location-specific errors.

Figure 4: Painted lady - Vanessa cardui

Figure 6: The setup within the flight cages included rearing enclosures with counted butterfly pupae, a container with host plants, and the camera trap setup with the colored panels.

The camera trap was powered by a solar panel and a recreational vehicle battery (Fig. 7). An LED light is attached to the camera.

Figure 7: Waterproof container with a battery as intermediate storage for solar power.

Maintenance

To ensure the setting functions continuously and avoids unexpected failures, it must be regularly maintained and checked to ensure the sensor box is working. This helps guarantee that data is collected and valuable time is not lost. In addition to managing the technical aspects, the care and feeding of the insects is, of course, particularly important. Ideally, feeding is done while the camera is not recording.

Materials

To test what attracts the insects best, we used panels in the colors yellow, blue, and wildflower meadow, each in two materials: acrylic (glossy and smooth) and rigid foam (matte and rough). The camera has LED lights that operates as flash, allowing insects to be recorded at night as well. This protocol focuses solely on the comparison of colors during day.